From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-366179-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 486 invoked by alias); 23 Aug 2011 19:17:36 -0000
Received: (qmail 477 invoked by uid 22791); 23 Aug 2011 19:17:36 -0000
X-SWARE-Spam-Status: No, hits=-2.9 required=5.0	tests=ALL_TRUSTED,AWL,BAYES_00
X-Spam-Check-By: sourceware.org
Received: from localhost (HELO gcc.gnu.org) (127.0.0.1)    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 23 Aug 2011 19:17:22 +0000
From: "marc.glisse at normalesup dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/50160] vector<bool> comparison very slow (no specialisation)
Date: Tue, 23 Aug 2011 19:28:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: libstdc++
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: marc.glisse at normalesup dot org
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Changed-Fields:
Message-ID: <bug-50160-4-KHJOvfC7Vx@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-50160-4@http.gcc.gnu.org/bugzilla/>
References: <bug-50160-4@http.gcc.gnu.org/bugzilla/>
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
X-SW-Source: 2011-08/txt/msg01953.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D50160

--- Comment #11 from Marc Glisse <marc.glisse at normalesup dot org> 2011-0=
8-23 19:16:40 UTC ---
(In reply to comment #8)
> For my application I should simply use an unordered_map and all the overh=
ead
> has gone. :D

Great.

> =E2=80=9CI haven't thought about the potential drawbacks of implementing =
vector<bool>
> backwards.=E2=80=9D
> What do you mean? Chunk wise backwards?

Er, yes, start filling each chunk from the most significant bit to the least
significant, but otherwise keep things the same.

> Hmm, reversing really is not that nice.

Any particular reason? Not that the current implementation is likely to cha=
nge
anytime soon, but if you found drawbacks it would be nice to have them writ=
ten
somewhere in case the same question ever arises again.